Boating Resources
Nautical Signal Flags
Each letter of the International Code of Signals has its own flag. Flown alone, a flag sends a standard message. Here they are with their phonetic names and single-flag meanings.
Nautical signal flag alphabet
A · Alfa
I have a diver down; keep well clear at slow speed.
B · Bravo
I am taking in, discharging, or carrying dangerous goods.
C · Charlie
Affirmative (yes).
D · Delta
Keep clear of me; I am maneuvering with difficulty.
E · Echo
I am altering my course to starboard.
F · Foxtrot
I am disabled; communicate with me.
G · Golf
I require a pilot.
H · Hotel
I have a pilot on board.
I · India
I am altering my course to port.
J · Juliett
I am on fire and have dangerous cargo on board; keep well clear of me.
K · Kilo
I wish to communicate with you.
L · Lima
You should stop your vessel instantly.
M · Mike
My vessel is stopped and making no way through the water.
N · November
Negative (no).
O · Oscar
Man overboard.
P · Papa
In harbor: all persons should report on board as the vessel is about to put to sea.
Q · Quebec
My vessel is healthy and I request free pratique.
R · Romeo
No single-flag meaning is assigned in the International Code of Signals.
S · Sierra
I am operating astern propulsion.
T · Tango
Keep clear of me; I am engaged in pair trawling.
U · Uniform
You are running into danger.
V · Victor
I require assistance.
W · Whiskey
I require medical assistance.
X · X-ray
Stop carrying out your intentions and watch for my signals.
Y · Yankee
I am dragging my anchor.
Z · Zulu
I require a tug.
Flag artwork is simplified for the web. Many states also require a red-and-white "diver down" flag when divers are in the water. Check your state rules.
Fly your name, too
Put your boat's name on the transom in crisp vinyl or dimensional acrylic letters.
Sources: Flag meanings from the International Code of Signals, NGA Pub. 102 (msi.nga.mil), checked October 8, 2026.